Berlin 2018 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 23: Graphene: Adsorption, Intercalation and Doping I (joint session O/TT)

TT 23.6: Talk

Monday, March 12, 2018, 16:15–16:30, MA 043

Graphene protected surface state on Ir(111) with adsorbed lithium — •Predrag Lazic¹ and Petar Pervan² — ¹Rudjer Boskovic Institute, Zagreb, Croatia — ²Institute of Physics, Zagreb, Croatia

It is well known that electronic surface states get strongly perturbed upon the chemical adsorption of very small amount of adsorbates. Adsorption of lithium atoms on Ir(111) is no expection to that rule. Iridium surface state get strongly perturbed and is practically eradicated - it can not be seen as a sharp peak in the ARPES measurement. However, if the graphene is added on top of Ir/Li system the iridum surface state magically reapears. We present a combined experimental and theoretical study of the described system. Using the density funcional theory calculations for large unit cells with disordered lithium atoms geometries on the (111) surface of iridium we were able to reproduce the results of the ARPES measurements -showing clearly that the surface state signal is strongly suppresed when lithium is adsorbed, while it is almost unchanged when lithium is intercalated (i.e. with graphene on top of it). Looking at the projected density of states we constructed a rather simple model explaining this behavior which seems to be general.